Magisk/app/src/main/java/com/topjohnwu/magisk/utils/ObservableHost.kt
2020-07-15 01:21:57 -07:00

82 lines
2.5 KiB
Kotlin

package com.topjohnwu.magisk.utils
import androidx.databinding.Observable
import androidx.databinding.PropertyChangeRegistry
/**
* Modified from https://github.com/skoumalcz/teanity/blob/1.2/core/src/main/java/com/skoumal/teanity/observable/Notifyable.kt
*
* Interface that allows user to be observed via DataBinding or manually by assigning listeners.
*
* @see [androidx.databinding.Observable]
* */
interface ObservableHost : Observable {
var callbacks: PropertyChangeRegistry?
/**
* Notifies all observers that something has changed. By default implementation this method is
* synchronous, hence observers will never be notified in undefined order. Observers might
* choose to refresh the view completely, which is beyond the scope of this function.
* */
fun notifyChange() {
synchronized(this) {
callbacks ?: return
}.notifyCallbacks(this, 0, null)
}
/**
* Notifies all observers about field with [fieldId] has been changed. This will happen
* synchronously before or after [notifyChange] has been called. It will never be called during
* the execution of aforementioned method.
* */
fun notifyPropertyChanged(fieldId: Int) {
synchronized(this) {
callbacks ?: return
}.notifyCallbacks(this, fieldId, null)
}
override fun addOnPropertyChangedCallback(callback: Observable.OnPropertyChangedCallback) {
synchronized(this) {
callbacks ?: PropertyChangeRegistry().also { callbacks = it }
}.add(callback)
}
override fun removeOnPropertyChangedCallback(callback: Observable.OnPropertyChangedCallback) {
synchronized(this) {
callbacks ?: return
}.remove(callback)
}
}
/**
* Injects boilerplate implementation for {@literal @}[androidx.databinding.Bindable] field setters.
*
* # Examples:
* ```kotlin
* @get:Bindable
* var myField = defaultValue
* set(value) = set(value, field, { field = it }, BR.myField) {
* doSomething(it)
* }
* ```
* */
inline fun <reified T> ObservableHost.set(
new: T, old: T, setter: (T) -> Unit, fieldId: Int, afterChanged: (T) -> Unit = {}) {
if (old != new) {
setter(new)
notifyPropertyChanged(fieldId)
afterChanged(new)
}
}
inline fun <reified T> ObservableHost.set(
new: T, old: T, setter: (T) -> Unit, vararg fieldIds: Int, afterChanged: (T) -> Unit = {}) {
if (old != new) {
setter(new)
fieldIds.forEach { notifyPropertyChanged(it) }
afterChanged(new)
}
}